This invention relates generally to an electrical cable assembly and, more particularly, to such an assembly incorporated in a segmented submersible pipe.
Power cables are utilized to interconnect surface power or instrumentation with motor-pump assemblies or other electrical devices used in submersible water-oil-gas well pumping operations. It is conventional practice to clamp the power cable to the down hole delivery tubing for support to interconnect the surface power to the submersible pump. The power cable is handled by means of a power operated hoist and reel on the surface. This method provides insufficient protection from abrasion, pinching or cutting of the cable insulation as the cable and pump delivery tubing are installed in a well casing. These shortcomings become very acute as the well casing bends and varies from its vertical orientation. Also, protection of the power cable from the environment of the well casing is non-existent. This environment may include dirt, rocks, debris, water, oil, gas, shock, vibration and high temperatures.
As described in the aforementioned copendig Panek et al application, the above-discussed disadvantages in the present method of interconnecting the power cable to a submersible motor driven pump may be overcome by mounting the cable and electrical interfacing components within segmented pipe sections to completely protect the components from abrasion, vibration, and the surrounding environment. More specifically, a pair of mating electrical connector members are mounted in the ends of the pipe sections. Each electrical connector member has at least one annular contact therein which is concentric to the longitudinal axis of its respective pipe. The contacts are dimensioned to slidably engage with each other when the pipes are coupled together in axial alignment. A conventional pipe coupling sleeve is threaded to the ends of the pipes to couple them together thereby mating the electrical connector members in the ends of the pipes and hence electrically interengaging the annular contacts therein. Because the contacts have an annular configuration, the pipes may be connected together using standard pipe joining components and methods. This in contrast to conventional pin and socket electrical connector members which are normally interengged by exerting relative axial movement, but no rotatable movement, toward each other by the use of a separate rotatable coupling nut which is mounted on the shell of one of the connector members.
In one of the embodiments disclosed in the aforementioned Panek et al application, the annular contacts in the mating connector members have approximately the same diameter and have front surfaces which are flush with the front faces of the connector insulators in which the contacts are mounted. Thus, when the connector members are interengaged, the annular contacts will engage each other in an axial abutting relationship. Good electrical contact is not always achieved by this butt contact arrangement due to differences in axial tolerances across the mating faces of the electrical connector members. The connctor disclosed in the aforementioned Oliver application overcomes this problem by providing a novel axially compressible annular spring contact in one of the mating connector members. In the preferred embodiment, the contact comprises a helically coiled spring formed as an annulus. The present invention overcomes the axial tolerance problem in a more inexpensive, versatile and trouble-free manner.